title: Involvement of intestinal P-glycoprotein in the restricted absorption of methylprednisolone from rat small intestine.
abstract: The interaction between steroid hormones and intestinal P-glycoprotein was investigated by measuring intestinal absorption from rat small intestine in situ. Prednisolone and hydrocortisone were rapidly absorbed from the entire small intestine. In contrast, methylprednisolone absorption was significantly retarded in jejunum and ileum by an intestinal efflux system. In the presence of verapamil an quinidine, the retarded absorption of methylprednisolone was completely recovered, suggesting that P-glycoprotein is responsible for the unique features of methylprednisolone absorption. A requisite for the substrate of intestinal P-glycoprotein seemed to be 6 alpha-methyl group in the steroid structure. Substrate specificity of intestinal P-glycoprotein to steroid hormones was shown to be in part different from those in other tissues such as adrenal gland. Little of all three steroid hormones disappeared in the supernatant of mucosal homogenate from rat small intestine, indicating that intestinal metabolism of these steroid hormones was relatively small.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Saitoh
authors.forename: M
authors.initials: M
authors.lastname: Hatakeyama
authors.forename: O
authors.initials: O
authors.lastname: Eguchi
authors.forename: M
authors.initials: M
authors.lastname: Oda
authors.forename: M
authors.initials: M
authors.lastname: Takada
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000378:metabolism*; D006854:Hydrocortisone / Q000378:metabolism; D066298:In Vitro Techniques; D007408:Intestinal Absorption / Q000502:physiology*; D007421:Intestine, Small / Q000378:metabolism*; D008297:Male; D008775:Methylprednisolone / Q000378:metabolism*; D011239:Prednisolone / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000893:Anti-Inflammatory Agents; D011239:Prednisolone; D006854:Hydrocortisone; D008775:Methylprednisolone